Hannover 2010 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 20: Atomic Clusters III (with MO)
A 20.6: Vortrag
Donnerstag, 11. März 2010, 15:45–16:00, F 303
Direct observation of fullerene plasmon oscillations in momentum space — •Sanja Korica1, Burkhard Langer2, Axel Reinköster1, Markus Braune1, and Uwe Becker1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin-Dahlem, Germany — 2Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin-Dahlem, Germany
An extended spherical object which gives rise to standing wave oscillations is C60 [1]. We performed new near threshold measurements for C60 in order to reveal the corresponding threshold behavior. The result was a surprise. The extension of the high energetic sinusoidal behavior to lower energies uncovers a phase jump of π/2 in the plasmon excitation region [2]. By subtraction of the extended regular oscillation from the experimental data we could unfold the oscillatory behavior of the plasmon excitations directly in momentum space for the first time. In addition, after subtraction of the plasmon oscillation the shell thickness dependent beating behavior of the partial cross sections was exhibited much more clearly than demonstrated before.
This shows, that Cohen and Fano’s formula [3] provides a very good measure for determining the large scale coherent photoionization behavior as prerequisite for the derivation of energetically more restricted kinds of behavior such as the plasmon oscillations exhibited directly in momentum space for the first time here.
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